The transport of molecules is fundamental to life as well as many engineered systems. Transport processes may be passive or active. One example of passive transport is diffusion. Diffusion is the process by which molecules move from regions of high concentration to regions of low concentration. In diffusion, the molecules move via Brownian motion and undergo a random walk that results in a net displacement of the molecules in the direction of lower concentration. Active transport processes utilize energy to move molecules. In some active transport processes, a force is applied to the system comprising the molecules, such that the molecules move in the direction of the force. Though molecules may be transported via passive or active means, the active transport of molecules is advantageous for many applications. Accordingly, improved articles and methods for the active transport of molecules are needed.